Vacuum brake for motor trucks



Jan. 20, 1953 c. M. STEELY VACUUM BRAKE FOR MOTOR TRUOKS 5 Sheets-Sheet1 Filed May 25, 1950 A INVENTOR. -ar'es 77?. SZeeZy,

ATTD RN EYE Jan. 20, 1953 c. M. s'rEELY 2,625,909

VACUUM BRAKE FOR MOTOR TRUCKS Filed May 25. 195o s sheets-sheet 2 I NVEN TOR.

'I ar'Zes 772. feiy ATTD RN EYS Jan. 20, 1953 c. M. sTEELY 2,625,909

VACUUM BRAKE FoR MOTOR TRUCKS Filed May 25, 195o s sheets-sheet s IN VENTOR.

ATTDRN EYE recess or cutout 49, Figure 4. The valve 48 is furtherprovided with a port 50 which communicates with the recess 49. Also,there is an arcuate passageway 5| arranged in the valve 48 for a purposeto be later described. Thus, by properly rotating or positioning thevalve 48 in the chamber 42, vacuum or air can be supplied to the uppersection 2|.

Projecting upwardly from the valve 48, or formed integrally therewith,is a sleeve or body portion 52, the body portion 52 projecting through acentral opening 54 in a cap 53. The cap 53 is threadedly connected tothe upper end of the housing 20. A suitable lever 55 is arranged inengagement with the body portion 52 and when the lever 55 is rotated,the body portion 52 and valve 48 will also be rotated, so that thepassageway 5| and port 50 can be arranged in registry with any of thebushings desired.

A nut 56 is detachably connected to the top of the cap 53, while asmaller nut 51 is detachably connected or threadedly connected to theupper end of the body portion 52, these nuts serving to insure thatthere is a fluid-tight seal between the moving parts.

'The valve 48 is provided with a longitudinally extending bore 58, and arod 59 slidably or reciprocably projects through the bore 58. The rod 59has its lower end shaped to define a pointed end or tip 60, and the tip60 is mounted for movement into and out of bridging relation withrespect to the opening 4| in the partition 40. Circumposed on the rod 59is a helical spring 6|, the spring 6| being interposed between thepartition 40 and a collar 62 which is secured to the rod 59. The helicalspring 6| serves to normally urge the rod 59 out of bridging or closingrelation with respect to the opening 4|. By means of the rod 59, thecondition or position of the diaphragm 24 can be maintained immobile.Thus, by moving the tip 60 into bridging or closing relation withrespect to the opening 4| at such times as the diaphragm 24 is beingpulled upwardly by vacuum in the section 2|, the diaphragm 24 will bemaintained immobile or stationary in this position. For causing turningmovement of the lever 55, a' bar 63 (broken lines), Fig. 2, is provided,and the bar 63 may be connected to the brake pedal of the vehicle, suchas a truck.

The apparatus shown in Figures 1 through 4 is used as follows: The coilspring 34 will normally maintain the conventional cam of the vehicle ina position so that rotation of the wheelsy of the vehicle is prevented.Then, to permit normal rotation of the vehicle wheels, the vehicleengine must be started and also the rod 48 is rotated by a suitablemeans, such as the lever 55 which may be connected to a foot pedal invthe v'ehicle. The valve 48 is rotated to the position shown in Figure4, whereby the vacuum is directed through the conduit 46 from the enginemanifold, then through the hollow bushingr 43, then through the port |9in the valve 48, next through the recess 49, and finally through theopening 4|, so that the resilient diaphragm 24 will be flexed upwardly.This upward movement of the diaphragm 24 causes the rod 21 to be raisedupwardly, whereby the leg 2 8 will be pivoted to thereby rotate theshaft 30l against the force ofV the spring 34. This rotation of theshaft 30 causes movement of the cam of the brake assembly so that thewheels of the vehicle will be free to rotate.

AThe tension of the coil spring 34 can be adjusted by rotating the shaft38, the shaft 38 being provided with wrench-engaging faces 89. Thus,rotation of the shaft 38 causes rotation of the gear wheel 35, since theworm 31 and teeth 36 are maintained or arranged in meshing engagementwith each other. Normally, the rod 59 is in the raised position shown inFigure 1, the rod 59 being urged into this position by means of thehelical spring 6|. Thus, vacuum pressure can pass freely through theopening 4|. However, the rod 59 can be lowered in the bore 58 by meansof a foot pedal, such as the foot pedal 88, so that the tip 60 closesthe opening 4|, whereby the diaphragm 24 will remain immobile inwhatever position it happens to be. It will be noted that the valve 48can be rotated from the position shown in Figure 4, so that air can flowthrough the bushing 45, through the ports I9 or 50 into the recess 49,and thence through the opening 4|, whereby the diaphragm 24 can bereleased, so as to permit the brakes of the vehicle to be unlocked.Also, the bushing 44 can be connected by suitable conduits to trailerbrakes or other independent brakes in the vehicle.

Referring to Figures 5 and 6 of the drawings, there is shown a modifiedbrake-operating mechanism. In Figures 5 and 6, the numeral 64 designatesan L-shaped bracket which is adapted to be secured to any part of avehicle or frame 65 by suitable securing elements, such as boltand-nutassemblies 66. A hollow, arcuate base 61 is secured to the bracket 64 bybolt-and-nut assemblies 68, and a conduit 69 projects through the base61. Arranged adjacent the upper portion of the base 61 is a partition 16which defines a chamber 1| and a valve 12 is rotatably arranged in thechamber 1|. The valve 12 has the same construction as thepreviously-described valve 48. For rotating the valve 12, the lever 55is again connected to the upper end thereof, and the bar 63 is pivotallyconnected to the lever 55 by a pin 13. The other end of the bar 63 ispivotally connected to a link 14 by a, pin 15, and a shaft 16 connectsthe link 14 to the brake or foot pedal 11. Thus, upon depression of themember 11 by the vehicle operator, the valve 12 can be selectivelyrotated in order to control the flow of air or Vacuum into the pipe orconduit 69. An opening 18 is arranged in the partition 10, and the tip66 of the rod 59 is again adapted to move into and out of bridgingrelation with respect to the opening 18.

A T-tting 19 is connected to the lower end of the pipe 69, andcommunicating or connected with the T-tting 19 is a conduit 80, theconduit being arranged in communication with one end of a housing 8|.Arranged in the housing 8| is a diaphragm 24 which functions in the samemanner as the diaphragm described in connection with the structure ofFigures 1 through 4. The diaphragm 24 is connected to a rod 21 so thatas the diaphragm 24 is moved by air pressure or vacuum, the rod 21 willbe reciprocated, and the rod 21 is pivotally connected to a link 28. Thelink 28 is operatively connected to a conventional cam assembly 82 whichis supported on a bracket 83. The bracket 83 is secured to the vehicleaxle 84. Movement of the link 28 causes the cam of the cam assembly 82to move the brake shoes into engagement with the brake drum 85, so as toapply the brakes to the vehicle upon proper setting of the valve 12.

For moving the tip 60 into closing relation with respect to the opening18 in the partition 10, a foot pedal 88 is provided. The foot pedal 88is mounted on the upper end of a bar 89, and

the lower end of the bar 89 is pivotally connected to one end of the arm99 by a pin 99. A pin 3l pivotally connects the arm 89 to the upper endof the rod 59. A bracket 9| is secured to the bottom of the floor board92 of the vehicle, and a pin 93 pivotally connects one end of the arm 89to the bracket 9|. The bar 89 is provided with a plurality of teeth 93which are adapted to engage with a plate 94 that is secured to thebottom of the floor board 92, whereby the foot pedal 98 or rod 59 can bemaintained immobile in its various adjusted positions.

Referring to Figures 5 and 6 of the drawings, there is shown av modifiedbrake-operating mechanism which operates substantially in the samemanner as the mechanism of Figures 1 through 4. Thus, the valve l2 canbe rotated by means of the member 'Vl' which is connected to the valve'l2 by means of the links 93 and 14. The valve l2 can be arranged sothat vacuum pressure goes through the conduit 46, then through thebushing 43, then throughthe valve 12, then through openings '13, andinto pipe or conduit 69. This vacuumatic pressure will consequently beexerted through the pipe or conduit 80, and this will cause flexing ofthe diaphragm 24 in the housing 9i. This flexing or movement of theresilient diaphragm 24 results in reciprocation of the rod 2'! and thiscauses movement of the link 28,

whereby the cam of the cam assembly 82 will be actuated and therebypermit rotation of the wheel. The rod 59 can be moved so that its tip 90closes the opening 18 in the partition 10, whereby the diaphragm 24 willbe maintained immoble. This depression of the rod 59 is caused 1 by thefoot pedal 88, the teeth 93 serving to maintain the foot pedal 88stationary in its adjusted position. Also, the valve 12 can be rotatedin order to permit air to enter the housing 8|, whereby the diaphragm 24can return to its normal position so as to again permit locking of thebrakes.

The brake-operating mechanism of the present invention is trouble free,will not freeze in cold weather and will not readily get out of order.The mechanism can be readily adapted to existing parts in a vehicle,such as atruck. The mechanism of the present invention is extremelysafe, because the truck brakes will not be released if the system isleaking in any place. In other Words, the system must be air-tight orvacuumproof. Also, the vehicle engine must be started before the brakescan be released, since vacuum has to be generated in the enginemanifold.

l claim:

l. n a brake system, a hollow housing including an upper section and alower section connected to said upper section, an annular resilientdiaphragm interposed between said upper and lower sections and connectedthereto, a rod having one end connected to said diaphragm and projectingthrough said lower section, a casing arranged exteriorly of saidhousing, a shaft rotatably mounted in said casing, a link having one endpivotally connected to said rod and its other end connected to saidshaft whereby movement of said diaphragm causes rotation of said shaft,a partition arranged in said upper section and defining a chamber, therebeing bushings communicating with said chamber, a valve rotatablyarranged in said chamber and provided with ports adapted to registerwith said bushings, the upper end of said valve projecting beyond saidupper section and defining a body member, a lever having one endconnected to said body member for rotating said valve, there being anopening in said partition, said valve being provided with alongitudinally extending bore, a rod reciprocably arranged in said boreand mounted for movement into and out of bridging relation with respectto the opening in said partition.

2. The apparatus as described in claim 1, and further including a coilspring for normally urging said rod out of bridging relation withrespect to said opening in the partition.

3. The apparatus as described in claim 1, and further including a c-oilspring circumposed on said shaft and positioned in said casing.

CHARLES M. STEELY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,905,984 Hill Apr. 25, 19332,059,069 Weiss Oct. 27, 1936 2,126,849 Weiss Aug. 16, 1938

